Serotonin is a happy chemical. Why isn it in anti-depressant pills?
Serotonin has a lot of different effects depending on where it is in the body. In the bloodstream, for example, it can cause the blood vessels to constrict raise blood pressure. In the brain, serotonin isn’t exactly a “happy chemical”. More serotonin doesn’t make you happier, it’s a much more complex set of interactions. When a serotonergic nerve fires, it releases serotonin into a synapse. After firing, the serotonin reuptake complex on this same neuron re-absorbs the serotonin, repackages it, and uses it again the next time it fires. An SSRI drug blocks this reuptake site, causing the serotonin to remain active in the synapse for much longer than it would otherwise. SSRIs take several weeks to show clinical effect even though they block the reuptake site immediately – more serotonin isn’t the complete answer. Complex changes occur between both the serotonergic neurons and the post-synaptic neurons after weeks of higher activity. After chronic SSRI administration, there’s more seroton
